A goods transporter or conveyer of the aforesaid known kind, and on which the present invention is based, is found described and illustrated in the U.S. Patent Specification 4,602,567.
Thus, this specification teaches an arrangement for conveying goods along a guide device with the aid of an electrically driven mechanism which includes two wheels for co-action with mutually opposite sides of the guide device when said device is inclined to the horizontal plane. The two wheels co-act with one another in a manner which enables the wheels to be driven synchronously by means of one single drive motor.
This is achieved with the aid of co-acting gears which ensure that the wheels rotate at mutually the same speed. When the guide device extends horizontally or substantially horizontally, the bottom wheel is not in co-acting engagement with a guide device surface, although the wheel is nevertheless driven synchronously with the upper wheel.
In the case of curved paths and guide device extensions, particularly when said paths and extensions deviate from the horizontal towards the vertical, one of the wheels will move along a longer conveyer distance on the guide device than the other wheel, which when the wheels are driven synchronously with one another means that one of said wheels will slip against the running surface on the guide device.
Furthermore the distance from one drive surface to the other and the cross-sectional configuration of the drive surfaces co-operating with the two synchronously driven wheels facing the running surfaces on the guide device are such that in a vertical conveying direction they conform with the configuration of the guide-device running surfaces in a manner such that a space formed between the drive surfaces will conform exactly to the cross-sectional profile of the guide device.
This known arrangement uses a specially constructed drive wheel, insofar as one of the wheel is divided into two wheel parts which are held together by a spring device.
The wheel parts are able to move relative to one another against a spring force, and therewith increase the distance between the drive surfaces, so that the wheel can adapt to local increases in dimensions of the guide device, such dimensional changes normally occurring at a transition from a horizontal or near horizontal extension to a vertical or near vertical extension of the conveyer part, or vice versa.